More 8-extruder fixups

Marlin/src/HAL/HAL_ESP32/HAL.cpp

   #if HAS_TEMP_ADC_5
     adc1_set_attenuation(get_channel(TEMP_5_PIN), ADC_ATTEN_11db);
   #endif
+  #if HAS_TEMP_ADC_6
+    adc2_set_attenuation(get_channel(TEMP_6_PIN), ADC_ATTEN_11db);
+  #endif
+  #if HAS_TEMP_ADC_7
+    adc3_set_attenuation(get_channel(TEMP_7_PIN), ADC_ATTEN_11db);
+  #endif
   #if HAS_HEATED_BED
     adc1_set_attenuation(get_channel(TEMP_BED_PIN), ADC_ATTEN_11db);
   #endif

Marlin/src/MarlinCore.cpp

             case 2: case 3: oldstatus = E1_ENABLE_READ(); ENABLE_AXIS_E1(); break;
             #if E_STEPPERS > 2
               case 4: case 5: oldstatus = E2_ENABLE_READ(); ENABLE_AXIS_E2(); break;
+              #if E_STEPPERS > 3
+                case 6: case 7: oldstatus = E3_ENABLE_READ(); ENABLE_AXIS_E3(); break;
+              #endif // E_STEPPERS > 3
             #endif // E_STEPPERS > 2
           #endif // E_STEPPERS > 1
         }

Marlin/src/gcode/config/M200-M205.cpp

       // setting any extruder filament size disables volumetric on the assumption that
       // slicers either generate in extruder values as cubic mm or as as filament feeds
       // for all extruders
-      if ( (parser.volumetric_enabled = (parser.value_linear_units() != 0)) )
-        planner.set_filament_size(target_extruder, parser.value_linear_units());
+      const float dval = parser.value_linear_units();
+      if ( (parser.volumetric_enabled = (dval != 0)) )
+        planner.set_filament_size(target_extruder, dval);
     }
     planner.calculate_volumetric_multipliers();
   }

Marlin/src/lcd/extensible_ui/lib/ftdi_eve_touch_ui/screens/temperature_screen.cpp

     case 22: UI_DECREMENT(TargetTemp_celsius, CHAMBER); break;
     case 23: UI_INCREMENT(TargetTemp_celsius, CHAMBER); break;
     #ifndef NO_TOOLHEAD_HEATER_GCODE
-    case  2: UI_DECREMENT(TargetTemp_celsius, E0); break;
-    case  3: UI_INCREMENT(TargetTemp_celsius, E0); break;
+      case  2: UI_DECREMENT(TargetTemp_celsius, E0); break;
+      case  3: UI_INCREMENT(TargetTemp_celsius, E0); break;
     #endif
     #if HOTENDS > 1
-    case  4: UI_DECREMENT(TargetTemp_celsius, E1); break;
-    case  5: UI_INCREMENT(TargetTemp_celsius, E1); break;
+      case  4: UI_DECREMENT(TargetTemp_celsius, E1); break;
+      case  5: UI_INCREMENT(TargetTemp_celsius, E1); break;
     #endif
     #if HOTENDS > 2
-    case  6: UI_DECREMENT(TargetTemp_celsius, E2); break;
-    case  7: UI_INCREMENT(TargetTemp_celsius, E2); break;
+      case  6: UI_DECREMENT(TargetTemp_celsius, E2); break;
+      case  7: UI_INCREMENT(TargetTemp_celsius, E2); break;
     #endif
     #if HOTENDS > 3
-    case  8: UI_DECREMENT(TargetTemp_celsius, E3); break;
-    case  9: UI_INCREMENT(TargetTemp_celsius, E3); break;
+      case  8: UI_DECREMENT(TargetTemp_celsius, E3); break;
+      case  9: UI_INCREMENT(TargetTemp_celsius, E3); break;
     #endif
     #if FAN_COUNT > 0
-    case 10: UI_DECREMENT(TargetFan_percent, FAN0); break;
-    case 11: UI_INCREMENT(TargetFan_percent, FAN0); break;
+      case 10: UI_DECREMENT(TargetFan_percent, FAN0); break;
+      case 11: UI_INCREMENT(TargetFan_percent, FAN0); break;
     #endif
     case 30:
       #define _HOTEND_OFF(N) setTargetTemp_celsius(0,E##N);

Marlin/src/module/temperature.cpp

     #elif DISABLED(HEATER_1_USES_MAX6675)
       temp_hotend[1].update();
     #endif
-    #if HAS_TEMP_ADC_2
-      temp_hotend[2].update();
-      #if HAS_TEMP_ADC_3
-        temp_hotend[3].update();
-        #if HAS_TEMP_ADC_4
-          temp_hotend[4].update();
-          #if HAS_TEMP_ADC_5
-            temp_hotend[5].update();
-            #if HAS_TEMP_ADC_6
-              temp_hotend[6].update();
-              #if HAS_TEMP_ADC_7
-                temp_hotend[7].update();
-              #endif // HAS_TEMP_ADC_7
-            #endif // HAS_TEMP_ADC_6
-          #endif // HAS_TEMP_ADC_5
-        #endif // HAS_TEMP_ADC_4
-      #endif // HAS_TEMP_ADC_3
-    #endif // HAS_TEMP_ADC_2
-  #endif // HAS_TEMP_ADC_1
+  #endif
+
+  #if HAS_TEMP_ADC_2
+    temp_hotend[2].update();
+  #endif
+  #if HAS_TEMP_ADC_3
+    temp_hotend[3].update();
+  #endif
+  #if HAS_TEMP_ADC_4
+    temp_hotend[4].update();
+  #endif
+  #if HAS_TEMP_ADC_5
+    temp_hotend[5].update();
+  #endif
+  #if HAS_TEMP_ADC_6
+    temp_hotend[6].update();
+  #endif
+  #if HAS_TEMP_ADC_7
+    temp_hotend[7].update();
+  #endif
 
   #if HAS_HEATED_BED
     temp_bed.update();